Proceedings Paper

Araidite models of two types of notched bar, namely three point bend and double notched bar, were subjected to an impact from a falling weight pendulum The resultant dynamic photoelastic patterns were captured using a 100 nano second duration spark source, a lens polariscope and a still camera. The spark was fired at different times, to an accuracy of 1 microsecond, for each reproducible impact and hence a sequential series of photographs built up. Dynamic stress intensity factors at the notch tips were measured from the photo-elastic fringes at the given times.